/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 */
#include "tomcrypt.h"

/**
   @file crc32.c
   CRC-32 checksum algorithm
   Written and placed in the public domain by Wei Dai
   Adapted for libtomcrypt by Steffen Jaeckel
*/
#ifdef LTC_CRC32

static const ulong32 _CRC32_NEGL = 0xffffffffUL;

#if defined(ENDIAN_LITTLE)
#define CRC32_INDEX(c) (c & 0xff)
#define CRC32_SHIFTED(c) (c >> 8)
#elif defined(ENDIAN_BIG)
#define CRC32_INDEX(c) (c >> 24)
#define CRC32_SHIFTED(c) (c << 8)
#else
#error The existing CRC32 implementation only works properly when the endianness of the target platform is known.
#endif

/* Table of CRC-32's of all single byte values (made by makecrc.c) */
static const ulong32 crc32_m_tab[] =
{
#if defined(ENDIAN_LITTLE)
      0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
      0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
      0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
      0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
      0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
      0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
      0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
      0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
      0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
      0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
      0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
      0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
      0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
      0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
      0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
      0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
      0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
      0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
      0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
      0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
      0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
      0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
      0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
      0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
      0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
      0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
      0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
      0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
      0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
      0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
      0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
      0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
      0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
      0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
      0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
      0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
      0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
      0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
      0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
      0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
      0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
      0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
      0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
      0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
      0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
      0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
      0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
      0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
      0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
      0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
      0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
      0x2d02ef8dL
#else
      0x00000000L, 0x96300777L, 0x2c610eeeL, 0xba510999L, 0x19c46d07L,
      0x8ff46a70L, 0x35a563e9L, 0xa395649eL, 0x3288db0eL, 0xa4b8dc79L,
      0x1ee9d5e0L, 0x88d9d297L, 0x2b4cb609L, 0xbd7cb17eL, 0x072db8e7L,
      0x911dbf90L, 0x6410b71dL, 0xf220b06aL, 0x4871b9f3L, 0xde41be84L,
      0x7dd4da1aL, 0xebe4dd6dL, 0x51b5d4f4L, 0xc785d383L, 0x56986c13L,
      0xc0a86b64L, 0x7af962fdL, 0xecc9658aL, 0x4f5c0114L, 0xd96c0663L,
      0x633d0ffaL, 0xf50d088dL, 0xc8206e3bL, 0x5e10694cL, 0xe44160d5L,
      0x727167a2L, 0xd1e4033cL, 0x47d4044bL, 0xfd850dd2L, 0x6bb50aa5L,
      0xfaa8b535L, 0x6c98b242L, 0xd6c9bbdbL, 0x40f9bcacL, 0xe36cd832L,
      0x755cdf45L, 0xcf0dd6dcL, 0x593dd1abL, 0xac30d926L, 0x3a00de51L,
      0x8051d7c8L, 0x1661d0bfL, 0xb5f4b421L, 0x23c4b356L, 0x9995bacfL,
      0x0fa5bdb8L, 0x9eb80228L, 0x0888055fL, 0xb2d90cc6L, 0x24e90bb1L,
      0x877c6f2fL, 0x114c6858L, 0xab1d61c1L, 0x3d2d66b6L, 0x9041dc76L,
      0x0671db01L, 0xbc20d298L, 0x2a10d5efL, 0x8985b171L, 0x1fb5b606L,
      0xa5e4bf9fL, 0x33d4b8e8L, 0xa2c90778L, 0x34f9000fL, 0x8ea80996L,
      0x18980ee1L, 0xbb0d6a7fL, 0x2d3d6d08L, 0x976c6491L, 0x015c63e6L,
      0xf4516b6bL, 0x62616c1cL, 0xd8306585L, 0x4e0062f2L, 0xed95066cL,
      0x7ba5011bL, 0xc1f40882L, 0x57c40ff5L, 0xc6d9b065L, 0x50e9b712L,
      0xeab8be8bL, 0x7c88b9fcL, 0xdf1ddd62L, 0x492dda15L, 0xf37cd38cL,
      0x654cd4fbL, 0x5861b24dL, 0xce51b53aL, 0x7400bca3L, 0xe230bbd4L,
      0x41a5df4aL, 0xd795d83dL, 0x6dc4d1a4L, 0xfbf4d6d3L, 0x6ae96943L,
      0xfcd96e34L, 0x468867adL, 0xd0b860daL, 0x732d0444L, 0xe51d0333L,
      0x5f4c0aaaL, 0xc97c0dddL, 0x3c710550L, 0xaa410227L, 0x10100bbeL,
      0x86200cc9L, 0x25b56857L, 0xb3856f20L, 0x09d466b9L, 0x9fe461ceL,
      0x0ef9de5eL, 0x98c9d929L, 0x2298d0b0L, 0xb4a8d7c7L, 0x173db359L,
      0x810db42eL, 0x3b5cbdb7L, 0xad6cbac0L, 0x2083b8edL, 0xb6b3bf9aL,
      0x0ce2b603L, 0x9ad2b174L, 0x3947d5eaL, 0xaf77d29dL, 0x1526db04L,
      0x8316dc73L, 0x120b63e3L, 0x843b6494L, 0x3e6a6d0dL, 0xa85a6a7aL,
      0x0bcf0ee4L, 0x9dff0993L, 0x27ae000aL, 0xb19e077dL, 0x44930ff0L,
      0xd2a30887L, 0x68f2011eL, 0xfec20669L, 0x5d5762f7L, 0xcb676580L,
      0x71366c19L, 0xe7066b6eL, 0x761bd4feL, 0xe02bd389L, 0x5a7ada10L,
      0xcc4add67L, 0x6fdfb9f9L, 0xf9efbe8eL, 0x43beb717L, 0xd58eb060L,
      0xe8a3d6d6L, 0x7e93d1a1L, 0xc4c2d838L, 0x52f2df4fL, 0xf167bbd1L,
      0x6757bca6L, 0xdd06b53fL, 0x4b36b248L, 0xda2b0dd8L, 0x4c1b0aafL,
      0xf64a0336L, 0x607a0441L, 0xc3ef60dfL, 0x55df67a8L, 0xef8e6e31L,
      0x79be6946L, 0x8cb361cbL, 0x1a8366bcL, 0xa0d26f25L, 0x36e26852L,
      0x95770cccL, 0x03470bbbL, 0xb9160222L, 0x2f260555L, 0xbe3bbac5L,
      0x280bbdb2L, 0x925ab42bL, 0x046ab35cL, 0xa7ffd7c2L, 0x31cfd0b5L,
      0x8b9ed92cL, 0x1daede5bL, 0xb0c2649bL, 0x26f263ecL, 0x9ca36a75L,
      0x0a936d02L, 0xa906099cL, 0x3f360eebL, 0x85670772L, 0x13570005L,
      0x824abf95L, 0x147ab8e2L, 0xae2bb17bL, 0x381bb60cL, 0x9b8ed292L,
      0x0dbed5e5L, 0xb7efdc7cL, 0x21dfdb0bL, 0xd4d2d386L, 0x42e2d4f1L,
      0xf8b3dd68L, 0x6e83da1fL, 0xcd16be81L, 0x5b26b9f6L, 0xe177b06fL,
      0x7747b718L, 0xe65a0888L, 0x706a0fffL, 0xca3b0666L, 0x5c0b0111L,
      0xff9e658fL, 0x69ae62f8L, 0xd3ff6b61L, 0x45cf6c16L, 0x78e20aa0L,
      0xeed20dd7L, 0x5483044eL, 0xc2b30339L, 0x612667a7L, 0xf71660d0L,
      0x4d476949L, 0xdb776e3eL, 0x4a6ad1aeL, 0xdc5ad6d9L, 0x660bdf40L,
      0xf03bd837L, 0x53aebca9L, 0xc59ebbdeL, 0x7fcfb247L, 0xe9ffb530L,
      0x1cf2bdbdL, 0x8ac2bacaL, 0x3093b353L, 0xa6a3b424L, 0x0536d0baL,
      0x9306d7cdL, 0x2957de54L, 0xbf67d923L, 0x2e7a66b3L, 0xb84a61c4L,
      0x021b685dL, 0x942b6f2aL, 0x37be0bb4L, 0xa18e0cc3L, 0x1bdf055aL,
      0x8def022dL
#endif
};

void crc32_init(crc32_state *ctx)
{
   LTC_ARGCHKVD(ctx != NULL);
   ctx->crc = _CRC32_NEGL;
}

void crc32_update(crc32_state *ctx, const unsigned char *input, unsigned long length)
{
   ulong32 crc;
   LTC_ARGCHKVD(ctx != NULL);
   LTC_ARGCHKVD(input != NULL);
   crc = ctx->crc;

   while (length--)
      crc = crc32_m_tab[CRC32_INDEX(crc) ^ *input++] ^ CRC32_SHIFTED(crc);

   ctx->crc = crc;
}

void crc32_finish(crc32_state *ctx, void *hash, unsigned long size)
{
   unsigned long i;
   unsigned char* h;
   ulong32 crc;
   LTC_ARGCHKVD(ctx != NULL);
   LTC_ARGCHKVD(hash != NULL);

   h = hash;
   crc = ctx->crc;
   crc ^= _CRC32_NEGL;

   if (size > 4) size = 4;
   for (i = 0; i < size; i++) {
      h[i] = ((unsigned char*)&(crc))[size-i-1];
   }
}

int crc32_test(void)
{
#ifndef LTC_TEST
   return CRYPT_NOP;
#else
   const void* in = "libtomcrypt";
   const unsigned char crc32[] = { 0xb3, 0x73, 0x76, 0xef };
   unsigned char out[4];
   crc32_state ctx;
   crc32_init(&ctx);
   crc32_update(&ctx, in, strlen(in));
   crc32_finish(&ctx, out, 4);
   if (compare_testvector(crc32, 4, out, 4, "CRC32", 0)) {
      return CRYPT_FAIL_TESTVECTOR;
   }
   return CRYPT_OK;
#endif
}
#endif
